1. Technical Field
The present invention relates generally to information retrieval in online computer networks and, in particular, to a method and system for recognizing dynamic data available on a computer network and triggering an action based on the changing state of the retrieved data.
2. Description of the Related Art
The World Wide Web is the Internet's multimedia information retrieval system. In the Web environment, client machines effect transactions to Web servers using the Hypertext Transfer Protocol (HTTP), which is a known application protocol providing users access to files (e.g., text, graphics, images, sound, video, etc.) using a standard page description language known as Hypertext Markup Language (HTML). HTML provides basic document formatting and allows the developer to specify "links" to other servers and files. In the Internet paradigm, a network path to a server is identified by a so-called Uniform Resource Locator (URL) having a special syntax for defining a network connection. Use of an HTML-compatible browser (e.g., Netscape Navigator or Microsoft Internet Explorer) at a client machine involves specification of a link via the URL. In response, the client makes a request to the server (sometimes referred to as a "Web site") identified in the link and, in return, receives in return a text document formatted according to HTML. The Web server can return many data object types (known as Multipurpose Internet Mail Extension (MIME) types), such as .gif and .jpeg files (graphics), .mpeg files (movies), .wav files (audio) and the like.
Thus, a user of a client machine typically "pulls" information from the Web using a Web browser. This process, however, assumes that the user can locate the information he or she desires at a particular time. Web content is constantly changing, and this fact has driven the development of so-called "push" technology. In a conventional "push" implementation, a user registers for information from a particular company or site and, from then on, the information is delivered to the user's machine when available or when the page has changed. Thus, information providers have more control over how their content is received and viewed.
Although such data delivery mechanisms have the advantage of enabling a user define what type of data he or she is interested in receiving, they have not found wide acceptance. One of the problems associated with pushing content to users in this manner is that the information is merely displayed to the user. Such known techniques do not afford the user the ability to specify when the information should be presented or how the information may be used. These systems simply display the changed data to the user.
It would be desirable to provide improved techniques for recognizing and acting upon dynamic data in a computer network such as the public Internet. The present invention addresses this problem.